Page 10, Stars II

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The Death of High Mass Stars

A massive star's core burns furiously fast. As it fuses larger atoms together, it does so faster and faster, trying to maintain adequate pressure on the inside to offset the gravitational pressure pushing in from the outside. Below is the time scale over which a star 25 times the mass of the sun, burns its internal fuel:

Burning Stage Surface T (K) Radius Duration (Seconds)

Hydrogen 40,000 6 Rsun 2.3 x 10¹⁴

Helium 16,000 70 Rsun 2.1 x 10¹³

Carbon 4,300 100 Rsun 5.2 x 10⁹

Neon 4,300 100 Rsun 3.9 x 10⁷

Oxygen 4,300 100 Rsun 1.6 x 10⁷

Silicon 4,300 100 Rsun 1.2 x 10⁵

Iron 4,300 100 Rsun 0.35

note: 3 x 10⁷ second = 1 year

When the core becomes solid Fe, there is no further energy production and the core immediately collapses within just a few seconds! The core collapse raises the temperature to several billion degrees. The Fe nuclei collide so violently they crush into neutrons.

The star undergoes a Supernova!

Burning Stage	Surface T (K)	Radius	Duration (Seconds)
Hydrogen	40,000	6 Rsun	2.3 x 10`¹⁴`
Helium	16,000	70 Rsun	2.1 x 10`¹³`
Carbon	4,300	100 Rsun	5.2 x 10`⁹`
Neon	4,300	100 Rsun	3.9 x 10`⁷`
Oxygen	4,300	100 Rsun	1.6 x 10`⁷`
Silicon	4,300	100 Rsun	1.2 x 10`⁵`
Iron	4,300	100 Rsun	0.35